Method and means for forming diaphragms.



G. G. PIERCE. METHOD AND MEANS FOR FORMING DIAPHRAGMS.

APPLIUATIOH FILED PEB.3,1913.

Patented Mar. 31, 1914.

f2? veni'ar W W2 M n m 7 UNITED STATES PATENT OFFICE.

GUY CARLETON PIERCE, OF LOS ANGELES, CALIFORNIA, ASSIGNOR T0 CALIFORNIA VALVE AND AIR BRAKE COMPANY, 01? LOS ANGELES. CALIFORNIA, A CORPORA- TION OF CALIFORNIA.

METHOD AND MEANS FOR FORMING DIAPHRAGMS.

Specification of Letters Patent.

Patented Mar. 31, 1914..

Application flied February 3. 1913. Serial No. 745,950.

To all whom it may concern Be it known that I, GUY CAnun'roN PIERCE, a citizen of the United States, residing in the city of Los Angeles, State of California, have im'ented a new and useful Method and Means for Forming Diaphragms, of which the following is a specification.

Diaphragms constructed according to the principles of this invention are more especially intended for use in the triple valves and pressure regulating valves of air braking systems, but are by no means limited to such use.

An object of this invention is to provide a method adapted for the forming of dla.

pbragms of a character that will be capable of supplying the necessary amount of movement to the reciprocatbry parts connected therewith, and yet the diaphragms be of a character that will never be bent into reverse curves during use, and hence will not suffer premature crystallization of the metal and consequent rupture along the lines where the metal bends when the diaphragms are in use. 'A diaphragm constructed according to the principles of this invention will wear for a long period of time even when subjected to heavy strain and frequent operation, and

this desirable result can be obtained even when the diaphragm is made of soft metal of a thickness of one two-hundredths of an inch.

The diaphragm may be constructed of a single sheet of metal or other material, or it may be constructed of a plurality of such sheets. The sheets of each diaphragm are preferably dealt with one at a time in the use of the method hereinafter described.

In applying the diaphragm to the triple valves of air brakes it is preferable after the sheets have been separately formed, to place together from two to four of them when the metal used is thin annealed copper, each sheet being of No. 34. or No. 36 B. S. stand ard gage.

A diaphragm constructed as just described will produce excellent results when used for the diaphragm of a triple valve of the character described in the patent granted to S. G. Neal, December 26, 1911, No. 1,012,694.

Referring to the accompanying drawings,

which illustrate the invention, Figure 1 is a pears after said diaphragm has been formed. Fig, 2 is a vertical mid-section of a forming device used in carrying out a modification of the method, the diaphragm blank being shown in place. Fig. 3 is a vertical midsection of still another diaphragm forming device which is, however, only a slight de parture from the device shown in Fig. 1. Fig. 4 is a partial section to illustrate the shapeof the diaphragm blank after the first step in shaping the diaphragm has been taken. Fig. 5 is a detail plan of a part of the operating means. Referring in detail to the draivings,.i-l-ie diaphragm 4, after it has been formed by this method and before removal from the forming device, appears as shown in Fig. 1, the forming device being of such construction that it itself, with the formed diaphragm, is adapted to operate as a pressure regulating or valve-operating device for the triple valves of air brakes, thereby rendering it possible to form the diaphragm in situ. Said diaphragm 4 divides the chamber shown in Fig. 1 into a lower compartment 5 and an upper compartment- 6, the casing consisting 0 an upper cap 7 and a lower cap or container 8. These two parts 7 and 8 are respectively provided with circular flanges 9 and 10, secured together by a series of cap-screws 11, the diaphragm being clamped between said flanges before the air pressure to form said diaphragm is applied thereto. Moreover, in putting the diaphragm blank in place the central portion thereof is clamped between the upper forming member 13 and the lower forming member 14, said members 13 and 14 having the general form of a pair of disks with curved faces which spoon into each other. The lower member 14 is preferably formed as a part of a head 15, carried by the operating rod 16, said operating rod playing through a stufling box 17. When the diaphragm is formed in site, as stated, the device shown in Fig. 1 is used for a valve operating device, the operating rod 16 being for the purpose of transmitting the motive power of the dia phragm to the extraneous part to be moved. The upper supporting member 13 is preferably a disk having a central aperture which receives the threaded upper portion 18 of the head 15, a clamping nut 19 being screwed l onto said portion to clamp the upper supall porting men her 13 against the diaphragm. The head also provided with an up Wardly extending stern 21. which. travels within a guielim dome A ijiompression spring 2.3 enga normally to in the parts in the depressed position to cause the lower end of head 15 to page the lower wall oi the member 8.

'iiil pressure introdnr-ed to chamber ough the inlet pipe In Fig. is snown modified form of device for curry-- out this method and this View will he rrihed next because it resembles the dcsice already described more closely than does the device shown in Fig. 2.

In Fig. 3 the compression spring '33 of i dispensed with and its function performed by fluid pressure admitted through pipe 2*. The rap 7 PIOVlilOd with an internal boss 23th which forms a stop against which the head 18 strikes to l mit the upward wouen'acnt of the diapiira formers 123 end 14.

liii owning the diaphragm by means of he device thus far described this method is arriril out as :i'ollons: Before the cap 7 is out in place, the open-ring rod 16 and head i are. put into operative position, tcjether with ti e :lir rniing member 141 that forms a si-i id head. then laid. on top of the lower forming moon her 14. said diaphragm being irovided with a ventral aperture to permit the same to be fitted over the extension 18 of the head. The diaphragm is this time in a perfectly flat condition. After the din hragi'n is thus laid in place. the member 13 is placed there over and not 19 is clamped down upon said member 13 to make an air tight fit hctween forming; members 13 and 14. This first step of the operation partially forms the diaphragm into he proper shape, as shown in Fig, 4 by reason of stretching the central portion of the diaphragm blank out of true alincnicnt and compelling the same to conform partially to the curved faces of the disks 1?; and 1:1. The upper ca 7 is now placed on ion of flange and bolted to said flange hy means of rap screws ll. The next step is now taken by admitting fluid nre through the inlet pipe 2 2 into the er chamber .3, and the formation of the diaphr n; thus completed by the pr. sure 0'? the iinh'l. forcing or stretching the same up to the position shown in Fig. 'l and also removing any irrrguhnfities in the metal than may have been caused by the clamping or the diaphragm blank.

The adjacent fac s of flanges 3 and it) are l tttlwl away; is slump in l ipu. l and 3. to prov .s a rirrunii'rrrntial inwardly Widen lug recess 27 in recciw the marginal portion of the movable part of the diz'lphrar' The curved faces of the siuiporting Inernbo 3. 5 and 14 are iiliewisc so spaced from. each the portion is of the head The diaphragm t other as to form approximately continuations of the Walls of recess 28.

It will he understood that the spring 23 in Fig. 1 serves to arrest the upward movement of the diaphragm forming plates and also, when the diaphragm is put into actual use as a motor, to return the diaphragm to its lowered position. when the fluid pressure i exhausted from beneath the diaphragm. in Fig. 3 the upward movement of the parts is arrested by the parts 18 and 26, and a fluid pressure means is provided as a substitute for the sprin for forcing the parts to their lowerunust position.

it will he understood that the special forms of apparatus illustrated in Figs. 1 and will not he cinpltq'ed for forming the diaplll'flgnlfil unless they to be formed, so to speak, in situ, that is, Where they are to he actually used. There the diaphragms are to or: removed after they are formed, I employ a simpler form of apparatus, as illusirateil, for example, in Fig. 2.

In Fig. 3 the diaphmgin is shown in the lowest position with the air pressure still agaimt the upper side thereof; in Fig. l the air prmun'e has just been admitted against the lower side of the diaphragin throwing the sonic. ago inst the upper "all of the tapered re (Jess '18. The air pressure will then more the diaphragm supports up to the position shown in irig. L, the diaphragm itself being exposed to strain. only along the narrow annular space between the mouths of recesses LT The greater portion of the strain is removed from the diaphragm by provid ing snliicient slack metal in the diaphragm to permit same to move from Wall to wall of the forming and. supporting members 13 and 1' and not rullle or kink the metal diaphragm. This is acctnuplished hy constructing said members I3 and M a fraction of an inch smaller than the actual diameter of the chamber in which the diaphragm is to opcrate, the intervening diaphragm surface only, being suhj ected to continued tension of fluid pressure the rest of the area of the diaphragm being supported by members 13 and It.

The tiisphra Uh l'mzning device shown in Fig. con {i at base plate 30, having an annular rt 3]. in its face. Said plate 30 supports a yoke the arms 33 of said yoke having reduesd. tin-ended. end portions 34 which extend through a flange 35 around lmso plate 50. Said threaded portions 34 are scoured in place by nuts 36 as shown, in Fig. Q. in the threaded bore 37 of yoke 32 operates a follower screw 38 to compress the follower or screw plate 33%) against the dia- Said screw plate 39 has on its loan-r surface sn annular concave reill of: a. broad shallow character, as shown, said recess being designed to give the pifipfli." eurva't are to the diaphragm when the latter is forced there-against by fluid pressure. In the center of a screw plate 30 is an annular rise 42, which engages a recess 43 in the screw plate 39. The diaphragm blank 41 is formed with a central aperture which fits over said rise 42, the central portion of said diaphragm being clamped between annular shoulder 44 of the base. plate and annular shoulder or face 45 of the follower plate 39. The peripheral portion of the diaphragm is at the same time clamped between the base plate and follower plate as shown, both clamping surfaces being air tight so that when fluid pressure is admitted to chamber 31 the portion of the diaphragm not in contact with the forming plate is positively forced up into the concave recess 40 of said forming )late and properly stretched and shaped. 'mall air vents 40 permit the air to escape from the concave recess 40. In forming the diaphra m, fluid pressure is admitted to the annu ar chamber 31 through pipe 46. Compression screw 38 is. preferabl connected with plate 39 by means of a split washer47 (see Fig. 5) which is placed around a head 48 formed on the lower end of said screw 38. The halves ofbaid split washer are held in place by screws 49 extending through small pieces '51. Screws 49 extending through holes 49 hold said washer to the screw plate 39.

Regarding Fig. 2, the object in forming the diaphragm in the manner illustrated in this view is to reduce the cost of manufacture in the following manner: By placing the diaphragm in a flat condition between the base plate 30 and the screw plate 39, the necessity of removing bolts 11 and nut 19 is eliminated when forming each individual diaphragm. As will be seen from this view, all that is necessary is to raise the screw 38 by the hand wheel (not shown), place the diaphragm blank 41 in position,admit the air through pipe 46 into annular chamber 31 for a period of five seconds, after which the air pressure is removed, screw 38 is lifted, and the completed diaphragm removed in perfect condition of the same contour as the diaphragms illustrated in Figs. 1 and 3.

It will be observed that in the device shown in Fig. 2 the forming plate 39 serves the same function, so far as the shaping of the diaphragm is concerned, as the disk 13 and the flanges of the cap 7 shown in Fig. 1.

Each sheet of metal for a diaphragm is formed separately. It has been found preferable to form said sheets separately owing to the fact that the copper is smooth and that it is therefore difficult to hold rigid and prevent a plurality of superimposed sheets from creeping, which will cause a ruffling of the metal due to the fact that the compression by air takes place between the peripheral portion and the central portion of each sheet. 'hen the attempt is made to form more than one diaphragm at a time, more than one hundred pounds pressure is required to force the metal to conform to the convex or concave surfaces. Forty pounds pressure per square inch is suflicient to form a diaphragm form No. 36 gage, or 5/1000of an inch thickness of metal. 1

One of the advantages of forming the diaphragm by this method as compared with forming said diaphragms by means of male and female dies is the eliminating of the fine adjustment required on such male and female dies where the thickness of metal to be formed is .005 of an inch or less. Furthermore, such dies would, under constant use, wear away and consequently lose their accuracy. Further, owing to the thinness of'metal used, it has been found impractical to use such male or female dies because mechanical pressure was not equally distributed throughout the ,surface of the blank out of which the diaphragm isbeing formed, resulting in rupture of the metal at the points of greatest strain; but by the application of the fluid pressure to one side of the diaphragm blank, said diaphragm blank is forced against a concavity on the other side thereof in such a uniform manner that even when the blank consists of a sheet of very thin, soft metal, the uniform distribution of the fluid pressure thereover forces the diaphragm blank into 'the proper shape without subjecting anyspart thereof to ru ture or excessive strain. f

I c aim:

1. In a diaphragm forming device, a base plate having an annular recess in the face thereof, a forming plate adapted to clamp a sheet metal blank between itself and said base plate, said forming plate having an annular concave recess registering with said recess of the base plate and making an air tight fit within said recess and also around the periphery thereof, and means to supply fluid pressure to the recess of the base plate to force a metal blank into said annular concave recess of the forming plate.

2. In a diaphragm forming device, a base plate having a fluid receiving space surrounding the central portion thereof, a forming plate adapted to cooperate with said base plate,said forming plate having a concave annular recess upon the face thereof which is directed toward said base plate, a suitable frame and a follower screw operating in said frame, said follower screw carrying said forming plate to move said forming plate to and from the operative position. and means to supply fluid pressure to the space in said base plate to force the diaphragm blank into the required shape.

3. In a diaphragm forming device, a base plate having a fluid receiving space surrounding the central portion thereof, a forming plate adapted to cooperate with said base plate, said forming plate having a concave annular recess upon the face thereof which is directed toward said base plate, a suitable frame, combined centering and clamping means carried by said frame to move said forming plate to and from the operative position, and means to sup ply fluid pressure to the space in said base plate to force the diaphragm blank into the required shape.

4. The herein described art of making diaphragms, consisting in air-tightly and unyieldingly clamping the blank both at its center and all around its edge, leaving an unclamped free annular portion, providing an annular concave shapin face at one side of said unclam ed part 0% the diaphragm, and applying uid pressure directly to the other side of the unelamped part of the diaphragm to thereby bodily stretch that portion of the diaphragm and permanently set and shape it against said concave face by said fluid pressure.

5. In a diaphragm forming apparatus, a base, a forming means adapted to clamp a sheet metal blank between itself and said base, said forming means having an annular concave recess in the face which faces the base, said base and said forming means serving to air-tightly clamp the blank at its Copies of this patent may be obtained to:

center and also around its edge, and means for applying fluid pressure to the face of the blank opposite the forming means to thus permanently set and shape the blank to the annular recess in said forming means.

6. The herein described art of making diaphragms, consisting in air-tightly clamping the blank at its center as well as all around its edge, leaving an unclamped free annular portion, and then applying fluid directly to one face of the blank under sufficient pressure to bodily stretch and set said annular unclamped portion of the blank.

7. The herein described method of shaping diaphragm blanks which consists in maintaining the central and peripheral'portions of a diaphragm blank in fixed position, leaving the intermediate annular portion free to yield, and then forcibly applying a fluid body to one side of said blank against said free portion thereof to bodily stretch and set said free portion tothe desired extent.

In testimony whereof I have hereunto signed my name in the presence of two snl'r scribing Witnesses at Los Angeles, in the l" county of Los Angeles and State of (,lalifornia, this 25th day of January, 1913.

G UY CARLETON PIERCE.

Witnesses Srnn one Gr. NEAL,

five cent: each, by addressing the Commluioner of Patents, Washington, D. 0.

Correction '1 Letters ate'ni Elm 1.0915763.

It is hereby'cerfified thitin Letters Patent No. 1,091,762, granted March 31, 1914,

npon: the application of Guy Carleton Pieree, of Loss- Angeles, California, foran improrferne'nt in Methods and Means for FormingDiaphragms, an error appears in printed specifibation requiring correction as follows: Page 4, for name of d secodddnentioned witness read Albert E Merrill; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and eealed this 5th day of May, A. D., 19M.

J- T. NEWTON,

Acting C'omm'issiofier of Patents.

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